A typical form of cushion portion has a cushion core comprising a foamed reaction mixture which is selectively covered on its front side by a cover such as a fabric and which on its rear side has a covering means which is stable in respect of shape, for example to provide a rigid support for the rear of the cushion core. Such a cushion portion can be produced by a process wherein a reaction mixture is introduced into a mold defining the cushion core, possibly after the introduction of a cover such as a fabric. The reaction mixture foams up to define the core in the mold which is closed by a first closure member and which thus defines a first mold cavity. The first closure member is then removed from the mold and replaced by a second closure member which defines between itself and the core that has remained in the first mold cavity, a second mold cavity into which a pouring or casting material is then introduced, which after setting forms the covering means which is stable in respect of shape, at the rear side of the core.
A form of process for producing a cushion portion with reaction mixtures of different hardnesses involves a procedure whereby a casting mold is closed by a first closure member, whereupon a first reaction mixture is introduced into the first mold cavity which is defined by the first closure member. After the reaction has occurred, the first reaction mixture fills the first cavity in the form of a first foam body. The first closure member is then removed from the mold and replaced by a second closure member, the first foam body remaining in the mold in that phase of the operation so that a second mold cavity is formed between the first foam body that has remained in the mold, and the second closure member. A second reaction mixture is then introduced into the second mold cavity and fills the latter after the reaction has taken place, in the form of a second foam body which forms a unit with the first foam body. That process which is disclosed in DE 38 23 584 C2 provides that a cover material is introduced into the mold, prior to its being closed by the firs t closure member, in closely contacting relationship with the mold. The soft-foam reaction mixture constituting the first reaction mixture then foams up to form a foam backing for the cover material. A hard-foam reaction mixture is introduced into the second mold cavity as the second reaction mixture, to form a support part for the cushion portion afforded by the foam backing on the cover material. It will be seen that the cushion portion produced by this process is of a predetermined and invariable shape.
A seat and more particularly a vehicle seat comprising a seat cushion and a backrest cushion and at least one inflatable cushion or pillow member is disclosed in DE 39 04 090 A1. In order to adjust that seat to the anatomical parameters of the respective occupant thereof, provided in the backrest cushion is at least one inflatable cushion or pillow or pad-like member having a porous, elastically yielding foam portion and an elastic air-tight foil which encloses the foam portion and which is provided with a valve for adjusting the amount of air for inflating the cushion member. A seat of that kind not only requires the appropriate cushion members to be produced and kept in store, for use as required, but it also involves a need for the inflatable cushion member to be disposed in the backrest cushion portion, which has an adverse effect on the manufacturing costs of such a seat.
DE 40 34 121 A1 discloses a seat having self-inflatable cushion or pad members which are disposed in the two side portions of the seat squab surface and in the two side portions of the backrest. The cushion or pad members are in fluid communication with valves which are provided for adjusting the amount of air therein. In order to enhance the level of operating convenience of that seat, all the valves can be simultaneously actuated by means of a common operating member. In terms of assembly and storage the same considerations apply here as in relation to the above-discussed seat of DE 39 04 090 A1.